Hydraulic lifting jack



May 24, 1932.

V R. KUMMEL HYDRAULIC LIFTING JACK 2 Sheets-Sheet 1 Filed Dec. 30, 1929 May 24, 1932.

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Filed Dec. 30, 1929 KUMMEL' 4 1,859,830

2 Sheets-Sheel; 2

Patented May 24, 1932 I UNITED STATES [PATENT OFFICE r EUGEN am, or

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Application filed December 30, 1929, Serial 1V0. 417,541, and in Switzefland December 24, 1928.

The object of the invention is to provide an improved hydraulic lifting jack, comprising a double lazy-tongs mechanism which is operated by means of a hydraulic cylinder. In the preferred construction the hydraulic cylinder is interposed between the members of the upper lazy tongs mechanism, the head of the jack carr in one part of the hydraulic cylinder, pre era bly the cylinder proper, and the middle pivot of the double tongs mechanism carrying the piston of the hydraulic cylinder. In practice, one hydraulic lifting jack is fixed to the under side of each of the two longitudinal main beams of the chassis of the motor car or other vehicle, preferably in the transverse middle plane of gravity of the car. The two jacks may be operated by means of a single pump which may be driven either from the motor of the motor car by means of a suitable clutch, or may also be a hand operated pump. The passage of the liquid, preferably oil, supplied by the common pump to the two lifting jacks, may be controlled by means of a single control valve in such a manner that either the one or the other side of the car is lifted or lowered as required.

The drawings show by way of example one construction embodying the features of the invention. i

Fig. 1 is an end elevation of the improved lifting jack, some parts being shown in section,

Fig. 2 is a front elevation, some parts heing shown in section,

Fig. 3 is a top view of the jack,

Fig. 4 is a front view of the control valve,

Fig. 5 is a sectional elevation of the control valve, and

Fig. 6 is a top view of the valve, partly section.

Referring first to Figs. 1 to 3, the liftingframe of the chassis, preferably to the under slde of a longitudinal beam of the chassis v in the transverse centre of gravity plane of the car. It will be understood that the two acks are used one on each side of the car. To the head 1 is hinged a cylinder head 3 to which are pivoted the upper links 2 of the double lazy-tongs mechanism. Within the cylinder 3 is adapted to slide a telescopic piston 4, 5. The lower end of the piston 5 is fixed within a tubular casing 6 which is pivoted at 7 to the middle links of the double lazy-tongs mechanism. The corner pivots of the double lazy-tongs mechanism are provided with springs 8 which tend to keep the mechanism in its closed position. The support or foot Q'of the jack is U-shaped in order to receive in the closedposition of the mechanism the casing 6 and the cylinder 3. The head of the cylinder 3 is provided with a socket or union 10 to which the pressureliquid supply conduit may be attached,

The supply of the pressure liquid, preferably oil, supplied by a pump, to the one or other of the twohydraulie cylinders, is controlled by a control valve shown in Figs. i and 5. This control valve is provided with an inlet socket 11 and a return socket 12 which are connected to the supply pressure pump (not shown). 13 and 14 are sockets for connection of pipes leading to the two hydraulic cylinders of the lifting jacks. A double-cone valve 15 controls ports 16 andl7 communicating respectively with the sockets 13 and 14. A further valve 18 serves for controlling, that is, opening or closing the port which communicates with the return socket 12. The valve should preferably be arranged near the drivers seat. It will be, understood that by operating the valve 15 oil may be admitted either to the one or to the other lifting jack whilst by operating the valve 18, oil may be caused to return to the supply valve whereupon the lazy-tongs mechanism will be collapsed by the springs 8. By the employment of a hydraulic cylinder for operating a lazy-tongs mechanism very considerable power may be produced and even very high ears may be lifted easily. In their collapsed condit-ion, the lifting 'jacks take up very little space and they may therefore be permanently fixed to the car.

' As the hydraulic cylinder is, in the collapsed condition of the jack, entirely enclosed within the tubular casing 6, access of dust and foreign matter into the cylinder and piston is entirely. avoided. In the open position of the lazy-tongs mechanism, the piston forms an effective guide for the links.

I claim:

1. A hydraulic jack for lifting motor cars, comprising in combination: a double lazytongs mechanism, a hydraulic cylinder and piston interposed between thetop and the middle joint of the said double lazy-tongs mechanism, a tubular casing fixed to the middle joint of the lazy-tongs mechanism and adapted to receive the hydraulic piston and cylinder in the collapsed condition of the jack, and a U-shaped support adapted to receive the said: casing in the collapsed condition of the 3:10

2. A hydraulic jack for lifting motor cars comprising in combination a double lazytongs mechanism, a head hinged to the top joint of the lazy-tongs mechanism, and adapted to be fixed to a frame portion of the car; a hydraulic cylinder fixed to the top joint of the lazy-tongs mechanism; a telescopic piston adapted to slide in said cylinder, a tubular casin fixed at its lower end to the lower end of 51c telescopic piston and fixed to the middle joint of the lazy-tongs mechanism, said tubular casing being adapt ed to receivethe telescopic piston and the hydraulic cylinder in the collapsed condition of the jack; a support carrying the lower joint of the lazy-tongs mechanism so shaped as to receive in the collapsed condition of the jack the said tubular casing; and springs acting upon the lateral joints of the lazytongs mechanism for collapsing the jack.

Signed atZurich, Switzerland, this 16th day of December, 1929.

REINHOLD K'UMMEL. 

